Gas turbine (GT) engines, which are commonly deployed on aircraft, derive energy by igniting a mixture of fuel and air within a combustion chamber to drive turbines that power the engine's compressor. The combustor system of one known GT engine includes a combustion chamber having a combustor dome assembly that comprises a heat-shield and an annular housing section having multiple apertures therethrough. A carburetor assembly is disposed through each of the apertures and supplies a mixture of fuel and air to the interior of the combustion chamber for combustion therein. Each of the carburetor assemblies comprises a fuel-injector receiving portion and an air flow modulator, which may be formed as an integral part of the combustor's heat-shield. The fuel-injector receiving portion may take the form of, for example, a bellmouth that receives a hook-shaped fuel injector within its mouth portion. The air flow modulator includes a plurality of circumferential veins that extends from an outer annular surface to an inner annular surface. These veins receive air from one or more compressors and direct it into the interior of the air flow modulator where the air is mixed with injected fuel. The combustible fuel-air mixture is then delivered into the combustion chamber and ignited. Ideally, the air flow modulator receives the compressed air at a uniform pressure along its outer surface to minimize cross-flow and turbulence, though this is not often the case in actual practice.
In the past, the injector bellmouth, the swirler/heat-shield assembly, and the combustor dome were rigidly coupled together using, for example, a welding or brazing process. This rigid type of coupling, however, is not designed to accommodate the spatial displacement that may occur between various parts of the combustion system due to thermal expansion. For example, the combustor dome and the swirler/heat-shield assembly are heated by the combustive gases and may move relative to the fuel injector and fuel injector bellmouth, which remain relatively cool during combustion. To better accommodate the differences in thermal expansion, alternative coupling means have been developed that employ various components (e.g., retaining rings, clips, etc.) to secure and align the swirler/heat-shield assembly with the combustor dome and the bellmouth, while simultaneously permitting limited movement between the bellmouth and the combustor dome and swirler/heat-shield assembly. Though overcoming some of the disadvantages associated with welding and brazing, such “flexible” coupling means employ multiple components and, consequently, are relatively complex and expensive to manufacture and install.
In addition to the above, in one known arrangement, the combustor-dome/heat-shield assembly accounts for a significant percentage of the total combustor weight and manufacturing cost. That is, each combustor dome assembly comprises eight unique parts and three retaining features (i.e. one each for the dome heat-shield, the dome swirler, and the bellmouth that contribute weight and cost to the combustor).
Considering the forgoing, it should be appreciated that it would be desirable to provide a simplified retaining means for use in conjunction with a combustor dome assembly that employs fewer components resulting in a lighter, less expensive combustor dome assembly.